Hello, kernel test robot noticed "BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc" on: commit: 24e44cc22aa3112082f2ee23137d048c73ca96d5 ("mm: percpu: enable per-cpu allocation tagging") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master [test failed on linus/mater 68b59730459e5d1fe4e0bbeb04ceb9df0f002270] [test failed on linux-next/master 73399b58e5e5a1b28a04baf42e321cfcfc663c2f] in testcase: trinity version: trinity-i386-abe9de86-1_20230429 with following parameters: runtime: 300s group: group-04 nr_groups: 5 compiler: gcc-13 test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G (please refer to attached dmesg/kmsg for entire log/backtrace) as we understand, this commit is not the root-cause of KCSAN issue, just make the issue change from form (1) to (2). furthermore, we don't understand why the issue happens randomly. but we failed to bisect the issue (1). so we just make out this report FYI, not sure if it could supply some hints to any real issues. 60fa4a9e23231721 24e44cc22aa3112082f2ee23137 ---------------- --------------------------- fail:runs %reproduction fail:runs | | | 281:999 -28% :998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_alloc <--- (1) 296:999 -30% :998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_block_update_hint_free 25:999 -3% :998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc/pcpu_chunk_populated :999 29% 292:998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_alloc <---(2) :999 27% 269:998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_block_update_hint_free :999 4% 44:998 dmesg.BUG:KCSAN:data-race_in_pcpu_alloc_noprof/pcpu_chunk_populated If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> | Closes: https://lore.kernel.org/oe-lkp/202407191651.f24e499d-oliver.sang@xxxxxxxxx [ 117.357897][ T3648] ================================================================== [ 117.358568][ T3648] BUG: KCSAN: data-race in pcpu_alloc_noprof / pcpu_block_update_hint_alloc [ 117.359222][ T3648] [ 117.359424][ T3648] write to 0xffffffff8559e600 of 4 bytes by task 3653 on cpu 1: [ 117.360048][ T3648] pcpu_block_update_hint_alloc (mm/percpu.c:602 mm/percpu.c:598 mm/percpu.c:923) [ 117.360554][ T3648] pcpu_alloc_area (mm/percpu.c:1260) [ 117.360960][ T3648] pcpu_alloc_noprof (mm/percpu.c:1835) [ 117.361393][ T3648] bpf_map_alloc_percpu (kernel/bpf/syscall.c:466) [ 117.361825][ T3648] prealloc_init (kernel/bpf/hashtab.c:338) [ 117.362211][ T3648] htab_map_alloc (kernel/bpf/hashtab.c:573) [ 117.362618][ T3648] map_create (kernel/bpf/syscall.c:1320) [ 117.362987][ T3648] __sys_bpf (kernel/bpf/syscall.c:5642) [ 117.363348][ T3648] __ia32_sys_bpf (kernel/bpf/syscall.c:5765) [ 117.363738][ T3648] ia32_sys_call (kbuild/obj/consumer/x86_64-randconfig-013-20240713/./arch/x86/include/generated/asm/syscalls_32.h:358) [ 117.364151][ T3648] do_int80_emulation (arch/x86/entry/common.c:165 (discriminator 1) arch/x86/entry/common.c:253 (discriminator 1)) [ 117.364578][ T3648] asm_int80_emulation (arch/x86/include/asm/idtentry.h:626) [ 117.365004][ T3648] [ 117.365203][ T3648] read to 0xffffffff8559e600 of 4 bytes by task 3648 on cpu 0: [ 117.365797][ T3648] pcpu_alloc_noprof (mm/percpu.c:1894) [ 117.366210][ T3648] bpf_map_alloc_percpu (kernel/bpf/syscall.c:466) [ 117.366627][ T3648] prealloc_init (kernel/bpf/hashtab.c:338) [ 117.367000][ T3648] htab_map_alloc (kernel/bpf/hashtab.c:573) [ 117.367400][ T3648] map_create (kernel/bpf/syscall.c:1320) [ 117.367766][ T3648] __sys_bpf (kernel/bpf/syscall.c:5642) [ 117.368120][ T3648] __ia32_sys_bpf (kernel/bpf/syscall.c:5765) [ 117.368503][ T3648] ia32_sys_call (kbuild/obj/consumer/x86_64-randconfig-013-20240713/./arch/x86/include/generated/asm/syscalls_32.h:358) [ 117.368907][ T3648] do_int80_emulation (arch/x86/entry/common.c:165 (discriminator 1) arch/x86/entry/common.c:253 (discriminator 1)) [ 117.369341][ T3648] asm_int80_emulation (arch/x86/include/asm/idtentry.h:626) [ 117.369761][ T3648] [ 117.369968][ T3648] value changed: 0x00000003 -> 0x00000000 [ 117.370454][ T3648] [ 117.370662][ T3648] Reported by Kernel Concurrency Sanitizer on: [ 117.371179][ T3648] CPU: 0 PID: 3648 Comm: trinity-c2 Not tainted 6.9.0-rc4-00089-g24e44cc22aa3 #1 [ 117.371943][ T3648] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 [ 117.372811][ T3648] ================================================================== The kernel config and materials to reproduce are available at: https://download.01.org/0day-ci/archive/20240719/202407191651.f24e499d-oliver.sang@xxxxxxxxx -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki